ABSTRACT The transition from high school to college is a developmentally sensitive period that is high risk for escalations in alcohol use. Although risky drinking is a common problem among freshmen, engagement in treatment services is very low. Low rates of engagement with treatment resources may occur because interventions target drinking directly at a time when students may be uninterested in changing their drinking. Moreover, with a targeted focus on alcohol use, current interventions also do not address the concerns of incoming freshmen, such as stress and sleep. Approaches that address the problems students are most concerned about, that also indirectly reduce drinking, may be particularly effective. Behavioral activation (BA) is an intervention that indirectly addresses psychopathy by guiding individuals to identify goals in their lives, and encouraging individuals to engage in reinforcing activities that align with their goals (Lejuez et al, 2001). While initially used to treat depression, BA has been efficaciously applied to substance use because BA acts on the same reinforcement process implicated in problem drinking. BA addresses drinking without specific reference to alcohol use by focusing on engagement in reinforcing activities that align with students? goals. A pilot study provided initial indication that a brief BA intervention administered in a semester-long freshman orientation course resulted in a significant decrease in drinking- related problems, compared to standard orientation (Reynolds et al. 2011). Notably, the approach never raised the issue of drinking unless raised by a student themselves. The purpose of the study is to conduct a fully powered cluster randomized trial testing BA administered in a semester-long (16 week) freshman orientation course, compared to a standard orientation course in 540 freshmen spread over 36 course sections (18 sections each of the BA and standard orientation format). A 5- month post-treatment assessment will measure durability of effects. Mediation analyses will test mechanisms of action. With this proposed R01, we will test a promising intervention with BA that addresses factors limiting participation in other programs by not targeting alcohol directly and by integrating an intervention into college curriculum, with the additional benefit of testing mediators to guide future work. This application represents a first step toward developing an intervention course that could be widely disseminated to address the persistent college drinking problem and its many consequences.